Surgical operations in surgery may damage biological tissues. Exposure of biological tissues to the air by incisions has been known to dry or oxidize biological tissues, resulting in damaged biological tissues. The damaged tissues may cause postoperative inflammation or the like to induce the adhesion between tissues that should be naturally separated. Such postoperative adhesion between tissues may lead to, for example, serious complications, such as ileus and infertility, in an abdomen. Various types of anti-adhesive materials have thus been developed to cover damaged sites of biological tissues for the prevention of adhesion.
Currently-known anti-adhesive materials have been mainly composed of biological polymer materials, such as polysaccharides and polypeptides, which are unlikely to cause adverse effects on living bodies. Such anti-adhesive materials are in various forms, such as powder, sheet, jelly, or liquid. Of these, liquid anti-adhesive materials have particularly attracted attention because of their operability of coating formed by being sprayed to target sites of biological tissues.
Of such anti-adhesive materials, for example, an anti-adhesive material disclosed in Patent Literature 1 includes a crosslinkable polysaccharide derivative having an active ester group reactive with an active hydrogen-containing group in a polysaccharide side chain introduced therein. The crosslinkable polysaccharide derivative can, upon contact with water under alkaline conditions, form a crosslinked structure through covalent bonding between the active ester group and an active hydrogen-containing group. Patent Literature 1 has disclosed, as a preferred embodiment, a method of preventing adhesion which includes applying an aqueous solution of the above crosslinkable polysaccharide derivative to a target site of biological tissues and then spraying an aqueous solution of a pH adjuster for generating alkaline conditions onto the target site to cause gelation of the crosslinkable polysaccharide derivative.
In addition, applicators capable of simultaneously spraying two chemical solutions, including the aqueous solution of the crosslinkable polysaccharide derivative and the aqueous solution of a pH adjuster, have been developed (e.g., Patent Literature 2). The use of such applicators allows the coating of the target site with an anti-adhesive material by one-time spraying. Since polysaccharides dissolved in water are more subject to deterioration than dry solid polysaccharides, aqueous solutions of polysaccharides are desirably prepared each time in surgical practice by addition of water to dry solid polysaccharides.